This article presents a review of the state of the art of research and development on Hg1−xCdxTe ‐Hg1−yCdyTe (0≤x,y≤1) heterostructures important for applications in the modern infrared detection technique. It deals with the fundamental physical properties, epitaxial growth methods, and applications of these structures. The most important experimental results relevant to this subject are described and discussed. Following a short survey of the physical properties of Hg1−xCdxTe, the travelling heater method for growing bulk crystals of Hg1−xCdxTe has been described and compared with the epitaxial growth techniques used to prepare thin films and layered structures of this compound. Some important aspects of substrate preparation procedures related to CdTe wafers have been discussed. Then the most important problems regarding the liquid‐phase, vapor‐phase, and molecular‐beam‐epitaxy methods of Hg1−xCdxTe ‐Hg1−yCdyTe (0≤x,y≤1) heterostructures have been studied. A comprehensive discussion of technology and the parameters of different heterostructure photodiodes made of Hg1−xCdxTe with electrically passive and electrically active heterointerfaces has been presented. The review is concluded with an overview of research problems relevant to HgTe‐CdTe superlattices and the surfaces and heterointerfaces of Hg1−xCdxTe.